Semiconductor processing typically includes various techniques performed on a substrate (e.g., a wafer) to form electronic devices such as integrated circuits. Examples of such techniques include layer formation using various deposition techniques (e.g., using electroless or electrochemical deposition, physical vapor deposition, or chemical vapor deposition), cleaning techniques, and chemical mechanical planarization.
Some of these techniques are aqueous or solvent based techniques. In other words, a semiconductor substrate can be processed by deploying processing chemicals onto the substrate using water or other liquids or fluids as a medium (i.e., “wet” processing). Various conditions can be used with these techniques to achieve different results. For example, various temperatures, flow rates, concentrations, etc. of the fluids can be used as desired.
Consistent application of the semiconductor processes is needed to achieve predictable and reliable results. For example, if a flow rate of a fluid over a substrate is inconsistent or uncontrollable, the same process performed twice may have very different results. Inconsistencies such as these lead to increases in failed devices, reductions in yields, and unreliable research data. The consistent application of the materials and processed used is also important in combinatorial techniques so that the results form the various regions can be reliably compared across one or more substrates.
Thus, what are needed are techniques for improving the consistency of semiconductor processes within a processing cell, across multiple regions, and subject to various processing conditions.